What is a Heart Attack?

A heart attack occurs when there is a severe blockage in an artery that carries oxygen-rich blood to the heart muscle. The blockage is usually caused by a blood clot that lodges in an artery that is already narrowed by the buildup of plaque (deposits of fat-like substances) along the wall of the artery. The sudden lack of blood flow to the heart muscle deprives the heart of oxygen and nutrients. If the blockage is not opened quickly, the heart muscle will suffer serious, permanent damage as areas of tissue die.

The medical term for a heart attack is acute myocardial infarction. Acute means sudden, myo refers to muscle, and cardia refers to the heart. The myocardium is the medical name for heart muscle. Infarct means that heart tissue has been destroyed or killed because it was deprived of oxygen for too long.

Sometimes a heart attack is caused by a coronary spasm – a coronary artery pinches itself off, restricting blood flow to the heart. This can happen in a normal artery but usually occurs in one that is already narrowed by the buildup of plaque along the artery wall. Women younger than 50 years of age who have a heart attack are more likely to have had a coronary spasm than men of this age or older men and women.

What is a silent heart attack?

A heart attack may occur without chest pain or any other symptoms; in this case, it is called a silent heart attack. It may be discovered days, weeks, or even months later during electrocardiogram ( ECG) testing. This kind of heart attack occurs more often in women than in men. People who have a silent heart attack tend to be about 7 years older than those who have more typical heart attacks (74 vs. 67 years) and more often have diabetes or heart failure. It’s likely that people with diabetes are at a higher risk for silent heart attacks because diabetes interferes with pain perception and may make you less likely to notice heart attack symptoms.

How does a heart attack develop?

A heart attack occurs when some part of the heart muscle stops getting blood and oxygen. This is usually caused by a clog in one or more of the arteries that carry blood and oxygen to the heart, as a result of coronary artery disease. The arteries become choked with fatty deposits called plaque over the course of many years. This process is called atherosclerosis. The name comes from the Greek words athero, meaning gruel or paste, and sclerosis, meaning hardness. The buildup of fatty deposits, including cholesterol and other lipids, gradually narrows the artery, allowing less blood to flow through. Eventually the fatty plaque may rupture (see below). Atherosclerosis is the main cause of a group of diseases called cardiovascular diseases – diseases of the heart and blood vessels

How does atherosclerosis develop?

Atherosclerosis develops when the normally smooth, muscular lining of the artery is damaged. This damage may be caused by smoking, high cholesterol, high blood pressure, or other heart disease risk factors . Fatty materials build up at the site of the injury creating a plaque. When the body’s immune system tries to repair the damage, it ends up doing more harm than good: the white blood cells that move in to repair the damaged artery make the lining sticky, more fatty deposits adhere, and the plaque gets bigger. Stable plaques are plaques that develop a hard, thick covering usually made up of calcium. They are the most common cause of hardened, narrowed arteries. Unstable plaques have a thinner, softer coating (a bit like a soft-boiled egg) that can be dislodged more easily.

Why does the gradual buildup of fatty plaque suddenly cause a heart attack?

Sometimes, the plaques that have built up in the arteries break off and cause a blockage. Plaque rupture occurs when the thin covering over the fat deposit is torn – similar to the popping of a pimple. Stress or heavy exertion can rupture a plaque. The body sees this burst plaque and, in the same way it would heal a cut finger, tries to repair the damage by forming a blood clot. This blood clot may block off the already narrow artery (coronary thrombus) causing a heart attack, or a piece of the clot may break away (embolus) and lodge in a different artery (causing an embolism). For example, if the embolus blocks an artery in the brain, this causes a stroke.

Plaques that lack a fatty center may also become disrupted, a process known as plaque erosion. It is not fully understood why or how these plaques begin to erode, but it occurs more frequently in women than in men. Smokers are also at greater risk for plaque erosion. Diagnostic tests can see how much fatty plaque buildup there is in your arteries, but it is hard to tell which plaques are likely to erode or rupture.

What are the symptoms of a heart attack?

There are two categories of heart attack symptoms: prodromal and acute. Prodromal symptoms are pre-heart attack symptoms that occur in the weeks and months leading up to a heart attack; acute symptoms are those you experience while you are having a heart attack.

The most common pre-heart attack symptoms in women are:

Unusual fatigue

Shortness of breath

Pain in the shoulder blade or upper back

The most common acute symptoms are:

Chest pain

Midback, neck, or jaw pain

Nausea or vomiting

Shortness of breath

Palpitations

Indigestion

Chest pain is the most common heart attack symptom in men and women. However, a substantial number of people, women in particular, do not experience chest pain during a heart attack. One study of 515 women who had heart attacks found that only about one third felt chest pain in the month before their heart attack, and nearly half of them did not experience it during their heart attack.

Generally, women are more likely than men to experience the so-called “atypical” heart attack symptoms, such as nausea, vomiting, weakness, or fatigue. This might be due to the fact that women simply describe more symptoms in greater detail than men do. Also, “atypical” is a bit of a misnomer because these symptoms are quite prevalent in both men and women.

Heart Attack – Action Plan

Call 911
Call 9-1-1 immediately. The longer you wait to get medical treatment, the greater the likelihood you will have severe, permanent damage to your heart or even die. The earlier you are treated, the more likely it is that damage to your heart will be kept to a minimum. Many treatments are most effective if given within 1 to 2 hours of when the heart attack begins. It is important to call emergency services because research shows that people who arrive at the hospital via ambulance are treated sooner than those who get there by their own means. Call 9-1-1 before you call your primary care physician. Calling your primary care physician before you call 9-1-1 can add to delays in receiving treatment.

Women having a heart attack are more likely than men to delay in seeking treatment. This is partly because women are less likely to realize that they are vulnerable to heart disease. Talk with your family and friends about the heart attack warning signs and the importance of acting fast by calling 9-1-1 within a few minutes – 5 at the most — if those signs persist. Explain to them that you will be treated faster if they call 9-1-1 rather than driving you to the hospital themselves.

After You’ve Called 9-1-1

Below are some additional preparations you can make; however, you should not lose precious time searching for pills or documentation before calling 9-1-1.

Chew an Aspirin. After calling for help, you should chew an aspirin (162 mg to 325 mg) to help prevent further clots developing. Only aspirin has this effect – not acetaminophen (Tylenol) or ibuprofen (Advil or Motrin). A chewed aspirin gets into the bloodstream more quickly than one swallowed whole. Enteric-coated or buffered aspirin is not absorbed as easily as regular aspirin. But if that is the only type of aspirin you have, crush the tablet before swallowing.

Nitroglycerin. If you’ve already had a heart attack, ask your physician about having nitroglycerin available in the event of a subsequent attack. If you experience chest pain that does not go away 5 minutes after taking 1 nitroglycerin tablet, call 9-1-1.17 You may take up to 3 nitroglycerin tablets (1 every 5 minutes) while waiting for the ambulance.

Important Information to Have On Hand

There is also some information you should always keep handy in case you suffer a heart attack: Find out the location of the nearest hospital that offers 24-hour emergency cardiac care and keep the address handy.

The American Heart Association recommends that doctors give a copy of the resting ECG to patients who have heart disease or who are at high-risk for a heart attack. If you have a copy of your resting ECG, give it to the emergency department doctors to help guide your treatment.

Make a list of medications you are taking and/or are allergic to. This will help ensure that you receive the appropriate treatments.

Heart Attack – Diagnosis & Treatment

How is a heart attack diagnosed?

Heart attacks are most often diagnosed by healthcare providers in an emergency room. Tests that are done to tell if you have had or are having a heart attack include:

Electrocardiogram (EKG or ECG): checks the heart’s rhythm and can locate the part of the heart where a heart attack might be occurring (or has occurred)

Blood tests: check for substances in the blood called biomarkers; increased levels of these biomarkers, such as troponin, are a sign that the heart cells are injured

Cardiac catheterization: an X-ray of the heart that locates the blocked artery

How is a heart attack treated?

Once you have been diagnosed with a heart attack, you will receive treatment to open the blocked artery. The catch-all term for these treatments is reperfusion therapy, which includes:

Clot buster drugs to dissolve the blood clot blocking the artery

Angioplasty and stent placement to widen narrowed arteries with a very small balloon, then prop them open with a tiny wire-mesh tube

Bypass surgery to improve blood supply to parts of the heart muscle that suffer from decreased blood flow

Heart Attack in Women

Do women have to worry about having a heart attack?

Yes. Heart disease, the cause of most heart attacks, is the #1 killer of both men and women in the US. About 3 million US women have had a heart attack. In 2004, 345,000 women suffered a new or recurrent heart attack. However, women develop heart disease later than men due to the protective effects of female hormones before menopause. For women, the average age of first heart attack is 70 years, about 5 years older than the average for men (66 years).

Lifetime Risk of Developing – Heart Disease

Age

Men

Women

After age 40

49%

32%

At age 70

35%

24%

Even though heart disease is more common in older women, more than 9,000 US women under 45 years of age suffer a heart attack every year. Black women develop heart disease at an earlier age than women of other races.

Are women more likely to die after a heart attack than men?

It depends. Women are more likely to die in the hospital and in the 30 days following a heart attack than men. This is largely because women are older and sicker than men by the time they have a heart attack. In the long run (from 6 months to 10 years after a heart attack), men and women are just as likely to survive their heart attacks.23-27 Older women (over age 75) generally do better than men of the same age and are less likely than men to die after a heart attack.

Heart attacks are less common in younger women (under age 50), but when they do occur, younger women are at a much higher risk of dying in the hospital than younger men. Studies have found that after a heart attack, women under age 50 are twice as likely to die in the hospital than men of the same age. The reasons for this are not fully understood.

The risk of dying from a heart attack for both men and women has fallen significantly in recent years as treatments have improved. In 2004, 75,000 women died from a heart attack, which is equal to about 2.5% of all women living with a heart attack in their past. Improved treatments have lowered death rates and women in particular have benefited; most recent studies have found that the gender difference often, but not always, disappears once you account for the fact that women who have heart attacks are usually older and sicker than men.

Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction).

Hennekens CH, Dyken ML, Fuster V. Aspirin as a therapeutic agent in cardiovascular disease: a statement for healthcare professionals from the American Heart Association. Circulation.